1. Field of the Invention
The present invention relates to a silver halide photographic light-sensitive material, and more particularly to a silver halide photographic light-sensitive material which contains cyan couplers excellent in the solubility as well as in the dispersing stability and which is capable of giving a dye image excellent in the color reproducibility as well as in the preservability during its storage over a long period of time.
2. Description of the Prior Art and Problems Thereof
The formation of a dye image by the use of a silver halide photographic light-sensitive material is effected generally in the following process: An aromatic primary amine-type color developing agent itself is oxidized when reducing the imagewise exposed silver halide photographic light-sensitive material's silver halide particles, and the oxidized product of the color developing agent then reacts with a coupler that is in advance contained in the silver halide photographic light-sensitive material to produce a dye image.
As the coupler, in order to make a color reproduction in the subtractive color process, usually three different couplers for the formation of yellow, magenta and cyan dyes are used.
These couplers each is usually dissolved into a substantially water-insoluble high-boiling organic solvent, if necessary, in combination with an auxiliary solvent, to be incorporated into a silver halide emulsion.
The fundamental nature required for each of these couplers includes that it should be well soluble in a high boiling organic solvent, that it should have a satisfactory dispersibility and dispersing stability, i.e., it should hardly deposit in a silver halide emulsion, that it should be excellent in the spectral absorbing characteristic and capable of forming a clear dye image having a satisfactory color tone in an extensive color reproducible range, and that the resulting dye image should be highly resistant to light, heat and moisture. Above all, for the cyan coupler the improvement of the following two points is essential: that the coupler should have almost no absorbability in the wavelength region other than its intrinsic spectrally absorbing wavelength region, and that it should have a satisfactory image preservability such as light resistance, heat resistance, moisture resistance and the like.
The conventionally known cyan couplers include 2,5-diacylaminophenol-type cyan couplers whose phenol is substituted in the second and fifth positions thereof with acylamino groups, which are described in, e.g., U.S. Pat. No. 2,895,826, and Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 112038/1975, 109630/1978 and 163537/1980.
The use of such a 2,5-diacylaminophenol-type cyan coupler, since its secondary absorption in the 400-450 nm region is small, enables to form an image satisfactory in the recolorability as well as in the blue-color reproduction, and also in the anti-dark-discoloration characteristics such as heat resistance, moisture resistance, etc., thus resulting in the formation of a largely improved dye image. However, such features-having 2,5-diacylaminophenol-type cyan coupler has the disadvantages that (1) its spectral minimum density in the 450-480 nm range is so high, while its lightness is so low that the color reproducible range is small, and its absorption in the 500-550 nm range is so high that the green-color reproducibility is deteriorated, (2) its resistance to light is poor, (3) the white background of the resulting image is discolored to be yellowish by light (hereinafter called Y-stain), and (4) the coupler is poor in the solubility and in the dispersing stability; and therefore the coupler does not meet the foregoing fundamental requirements for the nature of a coupler.